Development of Container Free Sample Exposure for Synchrotron X-ray Footprinting.

The method of X-ray footprinting and mass spectrometry (XFMS) on large protein assemblies and membrane protein samples requires high flux density to overcome the hydroxyl radical scavenging reactions produced by the buffer constituents and the total protein content. Previously, we successfully developed microsecond XFMS using microfluidic capillary flow and a microfocused broadband X-ray source at the Advanced Light Source synchrotron beamlines, but the excessive radiation damage incurred when using capillaries prevented the full usage of a high-flux density beam. Here we present another significant advance for the XFMS method: the instrumentation of a liquid injection jet to deliver container free samples to the X-ray beam. Our preliminary experiments with a liquid jet at a bending magnet X-ray beamline demonstrate the feasibility of the approach and show a significant improvement in the effective dose for both the Alexa fluorescence assay and protein samples compared to conventional capillary flow methods. The combination of precisely controlled high dose delivery, shorter exposure times, and elimination of radiation damage due to capillary effects significantly increases the signal quality of the hydroxyl radical modification products and the dose-response data. This new approach is the first application of container free sample handling for XFMS and opens up the method for even further advances, such as high-quality microsecond time-resolved XFMS studies

Detection of x ray sources in PROS

The problem of detecting discrete sources in x-ray images has much in common with the problem of automatic source detection at other wavelengths. In all cases, one searches for positive brightness enhancements exceeding a certain threshold, which appear consistent with what one expects for a point source, in the presence of a (possibly) spatially variable background. Multidimensional point spread functions (e.g., dependent on detector position and photon energy) are also common. At the same time, the problem in x-ray astronomy has some unique aspects. For example, for typical x-ray exposures in current or recent observatories, the number of available pixels far exceeds the number of actual x-ray events, so Poisson, rather than Gaussian statistics apply. Further, extended cosmic x-ray sources are common, and one often desires to detect point sources in the vicinity or even within bright, diffuse x-ray emission. Finally, support structures in x-ray detectors often cast sharp shadows in x-ray images making it necessary to detect sources in a region of rapidly varying exposure. We have developed a source detection package within the IRAF/PROS environment which attempts to deal with some of the problems of x-ray source detection. We have patterned our package after the successful Einstein Observatory x-ray source detection programs. However, we have attempted to improve the flexibility and accessibility of the functions and to provide a graphical front-end for the user. Our philosophy has been to use standard IRAF tasks whenever possible for image manipulation and to separate general functions from mission-specific ones. We will report on the current status of the package and discuss future developments, including simulation tasks, to allow the user to assess detection efficiency and source significance, tasks to determine source intensity, and alternative detection algorithms

HUMAN RESOURCE DEVELOPMENT PROFESSIONALS’ COMPETENCIES AND CAREER SUCCESS IN THE SERVICE INDUSTRY: A QUALITATIVE STUDY

The purpose of this study was to explore HRD professionals’ competencies leading to career success through an examination of their lived experiences of working in the service industry and to provide implications for HRD research and practice. Two research questions guiding this inquiry included: How do HRD professionals in the service industry experience career success? And how do HRD professionals in the service industry define and experience competencies leading to career success? To answer the two research questions, I conducted semi-structured interviews with 20 HRD professionals in the service industry. I then transcribed and coded the interview data and identified six themes including: (1) defining and experiencing career success through affect; (2) defining and experiencing career success as contribution to others; (3) defining and experiencing competency as KSAs and other attributes (e.g., capabilities, attitudes, values); (4) using the competency of relationship-building through trust and effective communication to define and experience career success; (5) implementing the competency of agility to define and experience career success; and (6) creating a unique competency mix by developing expert knowledge to define and experience career success. The study findings emphasize the need for HRD practitioners to become exemplars in their field, build credibility, be full organizational members who are credible, and develop unique competencies distinctive to their role. Future research should be conducted on HRD professionals’ perceptions of career success in the service industry. Further, given how emotional the topic of career success was to participants, scholars should explore the emotional well-being of HRD professionals. This study is limited to online interviews that were conducted because of interview participants’ busy schedule. Future research is called on to conduct in-person interviews, with the benefit of bodily presence, to collect richer data. For the sake of triangulation, I suggest adding multiple data collection methods such as observation, document review, and survey

Current-voltage Relation For A Field Ionizing He Beam Detector

Emerging interest in utilizing the transverse coherence properties of thermal energy atomic and molecular beams motivates the development of ionization detectors with near unit detection efficiency and adequate spatial resolution to resolve interference fringes of submicron dimension. We demonstrate that a field ionization tip coupled to a charged particle detector meets these requirements. We have systematically studied the current-voltage relationship for field ionization of helium using tungsten tips in diffuse gas and in a supersonic helium beam. For all 16 tips used in this study, the dependence of ion current on voltage for tips of fixed radius was found to differ from that for tips held at constant surface electric field. A scaling analysis is presented to explain this difference. Ion current increased on average to the 2.8 power of voltage for a tip at fixed field and approximately fifth power of voltage for fixed radius for a liquid nitrogen cooled tip in room temperature helium gas. For the helium beam, ion current increased as 2.2 power of voltage with constant surface field. The capture region of the tips was found to be up to 0.1 mu m(2) for diffuse gas and 0.02 mu m(2) in the beam. Velocity dependence and orientation of tip to beam were also studied

Multi-Dimensional Cost-Effectiveness Analysis for Prioritizing Railway Station Investments: A General Framework with an Application to the Italian Case Study

In recent years, several authors have highlighted the merits of the Cost-Effectiveness Analysis (CEA), e.g., compared to Cost-Benefits Analysis (CBA), particularly for small projects appraisal (e.g., revamping or extraordinary maintenance interventions) and when the impacts of the project are difficult to value or quantify in monetary terms. CEA is a quite consolidated technique, typically applied in practice when one specific impact prevails over the others. This research extends the concept of CEA to a multi-dimensional decision-making context, outlining a methodological framework that includes several criteria to assess the impacts of railway station revamping in urban contexts. The proposed method has already been applied for the project appraisals of five railway stations in Italy; this paper presents the application to a case study representing the typical configuration of a medium-sized Italian railway station. Results have shown that the proposed approach is a valid tool for both designers and infrastructure managers for prioritizing railway station investments in the presence of multiple strategic objectives that also conflict with each other. A multi-dimensional CEA can provide, in a communicative, lean, and effective way, the information on investment costs and the impacts that different policies, layouts, and technological solutions would have, creating the basis for a more transparent debate on resource allocation priorities. Finally, results have shown that the CEA is not only a method for project assessment, but also a tool for improving and directing the design towards the identification of interventions that allow the achievement of the key objectives set ex ante

TRA PERSONALITA' E MOTIVAZIONE: LA TEORIA DEGLI ORIENTAMENTI DI CAUSALITA'

1997/1998La teoria dell'autodeterminazione (Deci e Ryan, 1985) nasce per integrare in un modello unitario i risultati ottenuti nello studio della motivazione intrinseca e dei fattori che la influenzano. Gli orientamenti di causalità rappresentano l'approccio all'autodeterminazione livello di differenze interindividuali, stabilendo dei criteri per categorizzare i diversi modi in cui le persone interpretano gli eventi iniziatori o regolatori del proprio comportamento. Per la misurazione degli orientamenti di causalità, Deci e Ryan (1985a) hanno elaborato una scala, la Generai Causality Orientations Scale (GCOS), di cui vengono qui presentati tre studi sulla traduzione e la validazione in lingua italiana. Altre ricerche mettono in relazione gli orientamenti di causalità a costrutti diversi quali concezioni di sé, bisogni e scale di personalità. Ciò allo scopo di evidenziare il carattere tipico degli orientamenti di causalità, a cavallo tra personalità e motivazione. Si realizza poi, a livello sperimentale, il confronto tra locus di causalità, come viene espresso dagli orientamenti di causalità, e locus di controllo (Rotter, 1966). Contemporaneamente si verifica il contributo degli orientamenti 4i causalità all'illusione di controllo, soprattutto in relazione al benessere psicologico. Per quanto riguarda la possibilità di applicare la teoria dell'autodeterminazione alla spiegazione e alla previsione del comportamento, vengono introdotti due studi condotti in ambito scolastico. Da essi emerge l'importanza di considerare altri fattori strettamente legati alla motivazione, quali la relazionalità e le teorie sviluppate dagli individui a proposito dell'intelligenza. Nel capitolo conclusivo si inserisce la teoria degli orientamenti di causalità nel dibattito corrente su sé e identità, fornendo anche alcune indicazioni dal punto di vista metodologico, provenienti dai lavori presentati, per un utilizzo appropriato degli strumenti di misurazione degli stili motivazionali.X Ciclo1968Versione digitalizzata della tesi di dottorato cartacea. Nell'originale cartaceo mancano le pagg. 24, 116, 118, 13

Speckle Patterns With Atomic And Molecular De Broglie Waves

We have developed a nozzle source that delivers a continuous beam of atomic helium or molecular hydrogen having a high degree of transverse coherence and with adequate optical brightness to enable new kinds of experiments. Using this source we have measured single slit diffraction patterns and the first ever speckle-diffraction patterns using atomic and molecular de Broglie waves. Our results suggest fruitful application of coherent matter beams in dynamic scattering and diffractive imaging at short wavelength and with extreme surface sensitivity

Overview and status of the 0.5NA EUV microfield exposure tool at Berkeley Lab

A 0.5-NA extreme ultraviolet micro-field exposure tool has been installed and commissioned at beamline 12.0.1.4 of the Advanced Light Source synchrotron facility at Lawrence Berkeley National Laboratory. Commissioning has demonstrated a patterning resolution of 13 nm half-pitch with annular 0.35-0.55 illumination; a patterning resolution of 8 nm half-pitch with annular 0.1-0.2 illumination; critical dimension (CD) uniformity of 0.7 nm 1σ on 16 nm nominal CD across 80% of the 200 um x 30 um aberration corrected field of view; aerial image vibration relative to the wafer of 0.75 nn RMS and focus control and focus stepping better than 15 nm

Liquid Heterostructures: Generation of Liquid-Liquid Interfaces in Free-Flowing Liquid Sheets

Chemical reactions and biological processes are often governed by the structure and transport dynamics of the interface between two liquid phases. Despite their importance, our microscopic understanding of liquid-liquid interfaces has been severely hindered by difficulty in accessing the interface through the bulk liquid. Here we demonstrate a method for generating large-area liquid-liquid interfaces within free-flowing liquid sheets, which we call liquid heterostructures. These sheets can be made thin enough to transmit photons from across the spectrum, which also minimizes the amount of bulk liquid relative to the interface and makes them ideal targets for a wide range of spectroscopies and scattering experiments. The sheets are produced with a microfluidic nozzle that impinges two converging jets of one liquid onto two sides of a third jet of another liquid. The hydrodynamic forces provided by the colliding jets both produce a multilayered laminar liquid sheet with the central jet is flattened in the middle. Infrared microscopy, white light reflectivity, and imaging ellipsometry measurements demonstrate that the buried layer has a tunable thickness and displays well-defined liquid-liquid interfaces, and that the inner layer can be thinner than 100 nm.Comment: 30 pages, 8 figures, 1 table. Supplement: 19 pages, 8 figure